| A survey was made of microwave dielectric measurement techniques. The selection of a suitable technique was found to be dependent upon dielectric properties, frequency range, sample geometry, and available equipment. Characterization of a nonuniform electromagnetic field was required for accurate determination of the dielectric constant and loss. The measurement techniques were separated into two basic categories, which were transmission and resonant methods.;Resonant techniques were separated into two basic categories. The first was a perturbation method in which a cavity resonance was changed upon introduction of a sample. In the second technique, resonance was characterized within a dielectric sample. Low loss materials (<10('-3)) were able to be measured by resonant methods.;Ferroelectric ceramic materials exhibit a large dielectric relaxation at microwave frequency, and the cause has been attributed to piezoelectric grain resonance and domain wall motion. The main objective of this work was to measure the dielectric frequency response of antiferroelectric PbZrO(,3). Antiferroelectrics are not piezoelectric and the driving force for domain wall motion is small. It was therefore hypothesized that microwave dielectric relaxation of antiferroelectrics should not be of the same magnitude as ferroelectrics.;The dielectric properties of ceramic lead zirconate and rutile samples were measured up to 26 GHz. Rutile was measured as a reference material to determine microwave dielectric measurement accuracy. Lead zirconate measurements showed a small but significant decrease in the dielectric constant, and a large increase in the loss. The dielectric constant decreased 20% at 10 GHz from the 1 MHz value, and the dielectric loss increased by an order of magnitude to 0.04. The amount of relaxation was much smaller than that observed for ferroelectric materials such as BaTiO(,3), which had one-fifth of the low frequency dielectric constant at 10 GHz. Possible extrinsic and intrinsic loss mechanisms were offered as an explanation for the microwave dielectric relaxation of PbZrO(,3). Intrinsic mechanisms were associated low frequency lattice mode between Pb and the ZrO(,6) octahedra. Extrinsic loss mechanisms were ascribed to defects such as lead vacancies.;Transmission techniques had swept frequency capability, and a frequency range between 10 MHz and 26 GHz. A wide range of dielectric constant values were measured, but dielectric loss measurements were limited to above 0.005. Transmission methods were found to be the most useful for the microwave dielectric measurement of lead zirconate. |
